The invention is based on a fuel injection arrangement for internal combustion engines as defined hereinafter. In one such fuel injection arrangement, known from EP 0 307 947, which serves to supply fuel to an internal combustion engine, a high-pressure fuel pump fills a pressure reservoir chamber with fuel at high pressure, via a high-pressure line. From this pressure reservoir chamber, fuel injection lines lead to the individual injection valves protruding into the combustion chamber of the engine to be supplied; the pressure reservoir chamber is kept at a predetermined pressure by a pressure control device, so that independently of rpm, the injection pressure can be defined at the injection valves over the entire operating performance graph of the engine to be supplied.
To control the injection times and quantities of the injection valve, an electrically controlled valve is inserted into each injection line; with its opening and closing it controls the high-pressure delivery of fuel to the injection valve.
The known fuel injection arrangement has the disadvantage that the injection pressure at the injection valves is not freely selectable arbitrarily, but instead is dependent on the pressure in the pressure reservoir chamber. Nevertheless, achieving the most favorable possible fuel preparation for optimal, low-polluting combustion in the engine combustion chamber at every operating point requires being able to set not only the instant and duration of injection but also the injection pressure variably as a function of engine operating parameters.
These demands for a freely selectable injection pressure at the injection valve, which moreover must be adjustable within very short periods of time, are not met by the known fuel injection arrangement, since an adjustable pressure variation must be effected via the pressure reservoir system, which for functional reasons involves great inertia and because of this rigidity does not allow quick changes of pressure.